The Clotho dataset has two versions which are called Clotho V1 and Clotho V2. V1 has development, evaluation, and test splits whereas V2 has development, evaluation, validation, and test splits. Test splits can not be obtained since the publishers of Clotho use these splits for scientific challenges. V1 contains fewer audio clips in the development split than V2. There is a new validation split that has 1046 new development audio files in V2. Both versions have the same audio records in the evaluation and test splits. Since V2 is a newly published version, both V1 and V2 are used in our experiments. When Clotho V1 is used, the development split is divided, with 2000 audio clips in the development split and 893 audio clips in the validation split, since there is no validation split in V1. All of the splits have five captions for each audio clip. For these experiments, each audio file is used five times with their corresponding captions similar to [1]}. The vocabulary of Clotho contains 4366 distinct words.
